This invention relates generally to strand dispensing devices and more particularly to strand dispensing devices which prevent unwanted unwinding as the strand material is removed from a storage apparatus. Still more particularly, this invention relates to strand dispensing devices having a self-contained mechanical braking system which will remain in the engaged position irrespective of the orientation of the strand dispensing device until tension is applied to the strand material.
There are many instances in which strand material must be dispensed from a storage apparatus to some remote point. For example, a number of manufacturing processes, particularly in the textile industry, require strand material to be withdrawn from a storage apparatus, such as a spool, and fed to a remote point where further processing occurs. For simplicity, and by way of further example and not by way of limitation, the following discussion will be directed toward the use of strand dispensing devices by the utility industries.
The utility industries are faced with the problem of stringing heavy electrical conductors between spaced utility poles. Briefly, the method of stringing conductors between the poles involves the initial stringing of a lightweight flexible line, referred to as a pilot line, over pulleys mounted on the poles. Once the pilot line is extended to the desired length of conductor, a heavier line (called a bull line) is connected to the pilot line and is pulled back over the pulleys through the use of a power winch. The electrical conductor then is connected to the bull line and the bull line reeled in to string the electrical conductor between the utility poles. In some cases, the electrical conductor is light enough to be pulled over the pulleys by the pilot line without the need for the intermediate bull line.
With either approach, however, there are problems with respect to stringing of the pilot line. Usually the pilot line is coiled on a reel and the line is pulled from the reel with the initial stringing. When the reel has been set in motion by pulling the line, the inertia of the reel tends to keep it in motion. As a result, the reel spools out the line even after the pulling has stopped. This problem would prevent the use of a pilot line in many instances where a sagging line would interfere with the vehicular or pedestrian traffic.
In the past, this problem has been solved by providing a friction brake to constantly retard the rotation of the pilot line reel. This approach has eliminated the spewing of the line from the reel but has created a number of new problems. One of these problems is encountered when the pilot line is strung for great distances, for example, up to half a mile. When the weight of the rope and the friction of the pulleys are added to the constant friction of the brake, the resultant retarding force is greater than the force capable of being exerted by an operator. Other problems posed by devices of this type are relatively high costs and undue complexity.
For example, U.S. Patent 3,595,529 issued to W. T. Stull et al. on July 27, 1971 discloses a payout assembly which prevents unwanted unwinding as strand material is removed from a storage reel. While the Stull et al. device works well, it relies on a hydraulic brake system which is relatively complex and costly. Similarly, U.S. Patent 3,258,219 issued to R. T. McLendon on June 28, 1956 teaches a tension payoff mechanism for cable reels which utilizes a hydraulic brake system which is subject to the same cost and complexity drawbacks as the Stull et al. device.
U.S. Patent 3,899,143 issued to R. J. Slezak on Aug. 12, 1975 teaches a tension control device which relies on a pneumatic arrangement to regulate the tension required to remove the strand material from the storage reel. The Slezak device must, however, be oriented such that the brake is actuated by gravity.
U.S. Patents 2,488,492 issued to P. K. Dumbleton on Nov. 15, 1949, 3,069,107 issued to R. F. Hirt on Dec. 18, 1962 and 3,228,624 issued to C. L. Brinkman on Jan. 11, 1966 each teach strand dispensing devices which have mechanical braking systems. In each of these devices, however, gravity is utilized to actuate the braking system and thus the devices must be properly oriented.
While the foregoing patents disclose strand dispensing devices which are intended to prevent unwanted unwinding of the strand material during removal from a storage apparatus, they lack the aspects of the present invention wherein a self-contained mechanical braking system is used to prevent unwanted unwinding of the strand material. The self contained mechanical braking system does not rely on complex and costly hydraulic or pneumatic brake arrangements and is actuated by a mechanical means rather than by gravity. This latter aspect permits the present invention to be utilized irrespective of its orientation and renders the present device capable of being embodied in a portable form for use in relatively inaccessible locations.
It is, therefore, an object of the present invention to provide a device having a self-contained mechanical braking system which will be engaged irrespective of the orientation of the strand dispensing device.
It is a further object of the present invention to provide a strand dispensing device which will prevent unwanted unwinding as the strand material is removed from a storage apparatus.
These and other objects of the present invention will be readily apparent when considered in reference to the following description and claims and when taken in connection with the attached drawings to which they relate.